Calling the scheme, which allows employees to surrender some of their rights in return for shares in the company that they work for, a wasteful “pet project,” Clegg said his party would have chosen to increase the tax-free allowance and give those on low incomes an extra £140 per year instead.

New figures suggest that the scheme may be having a minimal effect. A freedom of information request to the Department for Business, Innovation and Skills revealed that just 19 inquiries have been made about the scheme since July.